Module 8 Cellular Energy

Elena is taking a guided hike through a New Hampshire forest in October to enjoy the changing colors of autumn leaves. Her guide explains that the leaves change color as the green pigment chlorophyll used in photosynthesis decomposes. Another hiker asks the guide to explain photosynthesis. Which is the guide’s answer?

• Photosynthesis is a process heterotrophs use to make energy

• Photosynthesis is the process autotrophs use to make energy

• Photosynthesis is the process heterotrophs use to make sugars

• Photosynthesis is the process autotrophs use to make sugar

What describes the first law of thermodynamics?

• Energy can be converted from one form to another, but it cannot be created nor destroyed

• Energy cannot be converted without the loss of usable energy

• The energy of a system approaches a constant value as the temperature approaches absolute zero

• Energy cannot be converted from one form to another without a net gain of usable energy

Answer explanation

The first law of thermodynamics states energy cannot be created nor destroyed. It can change forms though leading to a loss of useable energy.

What type of organism converts light energy from the Sun into chemical energy?

• a heterotroph

• a detritivore

• a chemoautotroph

• a photoautotroph

Answer explanation

A heterotroph must consume something for energy, a detritivore decomposes organic matter for energy, a chemoautotroph does create its own energy but does so through chemosynthesis not light energy.

Why is glycolysis an anaerobic process?

• Glycolysis does not produce carbon dioxide in its steps

• Glycolysis produces carbon dioxide in its steps

• Glycolysis utilizes oxygen in its steps

• Glycolysis does not utilize oxygen in its steps

Answer explanation

Glycolysis happens without oxygen meaning it is anaerobic. Anaerobic is without oxygen and has nothing to do with the presence of carbon dioxide.

Why is there a net yield of two, not four, ATP molecules in glycolysis?

• 2 molecules of ATP are used to begin glycolysis

• 2 molecules of ATP are produced during glycolysis

• 2 molecules of ATP are produced from ATP synthase

• 2 molecules of ATP are used to complete glycolysis

Answer explanation

It takes energy from ATP to split glucose. During the process of glycolysis, a total of 4 ATP are produced. 4 ATP - 2ATP= 2 ATP

Which process does not occur in the mitochondria?

• Electron transport chain

• glycolysis

• Krebs cycle

• preparatory reaction

Answer explanation

Glycolysis takes place in the cytoplasm.

Which of the following is an autotroph

• daisy

• mushroom

• wolf

• earthworm

Answer explanation

Mushrooms are decomposers, wolfs are autotrophs, earthworms are detritivores

Where is the location of the light-dependent reactions?

• granum

• stroma

• thylakoid

• matrix

Answer explanation

The light-dependent reaction is the electron transport chain. The ETC happens along the thylakoid membrane.

Light-absorbing molecules such as chlorophyll are called

• grana

• stroma

• thylakoids

• pigments

Answer explanation

Grana is sacks of thylakoids, Stroma is the fluid filled space inside the chloroplast, thylakoids are the disk like membranes in the chloroplast.

Which of the following defines metabolic pathways?

• A series of chemical reactions in which organic molecules are broken down to release energy

• a series of chemical reactions in which mechanical energy converts into chemical energy

• a series of chemical reactions in which the product of one reaction is the substrate for the next

• A series of chemical reactions in which light energy converts into chemical energy